1. Field of the Invention
The present invention relates generally to protecting digital graphical information from being copied. More particularly, the present invention relates to protecting digital data using a combination of cryptographic techniques and physical encapsulation of digital data from the time it is submitted for processing until the time it is provided to the monitor in an analog form.
2. Description of Related Art
As a result of popular acceptance of the Internet and other mechanisms used to compress, store and/or distribute digital video information, multipurpose platforms such as personal computers ("PCs") have become viable platforms for viewing and retrieving digital video information. Prior to the popular acceptance of video on multipurpose platforms, video content was usually viewed on consumer electronic devices dedicated to retrieving and displaying such information. Despite the rising popularity of multipurpose platforms, video content providers have been reluctant to provide substantial content for the PC platform.
One reason for this reluctance involves the ease in which digital representations of video content can be illicitly copied and resold with no degradation of quality. Without a system to protect digital data on a PC, the risk of fraudulent use and devaluation of their digital content is too great.
Under conventional techniques, digital video sources usually transmit digital video content to the PC in bulk-encrypted form. The content is received either electronically (via Internet) or from a physical medium (e.g. Digital Versatile Disk ("DVD"). Before an authorized user can view the video content, it must first be decrypted. The decrypted data is in a compressed format (e.g. Motion Picture Experts Group ("MPEG")). The decrypted data is decompressed prior to being processed by a graphics controller. Thereafter, the decompressed processed data is loaded into a frame buffer for later retrieval and use by a display device.
Frame buffers store information until needed by a display device. Different processes involved in generating a digital data frame and creating an image from the digital data frame often results in timing differences which necessitates a frame buffer memory. The frame buffer memory, usually a large block of memory, stores the intermediate images until the display device can process them. Different device fabrication techniques make it desirable to fabricate large blocks of memory separately from processing components used in decompressing and decoding video signals.
Image display electronics retrieve the images from the frame buffer and convert the digital representation of a frame into an analog signal, usually using a digital/analog ("D/A") converter as each frame is needed by the display device. The analog information is sent to the display device (often a monitor) which produces an image for viewing or recording.
The graphics control electronics may further include support circuits which track or "meter" the amount and/or purpose of processed information, maintain billing records, and communicate with a transaction clearing house.
The many processing stages used in converting the bulk encrypted digital video content into a display device useful format provides many opportunities for an unauthorized copier to insert electronics which captures the original unencrypted digital original. Prior art, software-only mechanisms for managing the decrypting, metering, billing operations, and image display do not provide sufficient protection of the digital content. Unauthorized users can "hack" such software to obtain the original unencrypted digital "master". Thus, a need exists for providing a secure method of retrieving and distributing such video content.